File > Export helps you change your presentation into a different format, such as PDF, video, or Word-based handouts. All these options are covered below.
If you simply want to "export" a file (in its current .pptx format) to a different storage system, such as a flash drive, plug that flash drive into your computer and use File > Save As (or Save a Copy) to save to that new location.
Create a PDF
You can convert your presentation to PDF or XPS to share with others.
Click the Create PDF/XPS button.
In the File Name box, enter a name for the file, if you haven't already.
In the Save as type list, ensure that PDF (*.pdf) is selected.
If you want the file to open in the selected format after saving, select the Open file after publishing check box.
If the document requires high print quality, click Standard (publishing online and printing).
If having a smaller file size is more important than print quality, click Minimum size (publishing online).
Click Options to set the pages to be printed, to choose whether markup should be printed, and to select output options. Click OK when finished.
Create a video
You can turn your presentation into a video file that can be watched without using PowerPoint.
See Turn your presentation into a video for the details.
Package a presentation for CD
You can create a package for your presentation and save it to a CD or USB drive so that other people can watch your presentation on most any computer.
See Package a presentation for CD or USB flash drive for the details.
If you want to use the editing and formatting features of Word, you can work on and print your handouts using Word.
See Edit or print PowerPoint handouts in Word for the details.
Change the file type
Change File Type is the same feature as the traditional Save As command. You select the underlying type of file you want, then click the Save As button. The original file is kept in its current format and closed, and a new copy of it is opened and saved in the format you've chosen.
Publish to Microsoft Stream
(This feature is available to Office 365 subscribers who are part of an organization.)
After you save your presentation as a video, you can upload the video to a video-sharing site named Microsoft Stream that only people in your school or organization have access to. Those people can watch the video in a browser.
See Save a video to Microsoft Stream for more details.